The Earths atmosphere is a layer of gas and suspended solids extending from the Earths surface up many thousands of miles, becoming increasingly thinner with distance but always held by the Earths gravitational pull. The atmosphere is mostly composed of nitrogen (78%) and oxygen (21%) . Other gases that make up the atmosphere include argon, carbon dioxide, neon, helium, and hydrogen, among others. These gases are listed below, with the top four making up 99.998% of all gases:

• Nitrogen (N2): 78%
• Oxygen (O2): 21%
• Argon (Ar): 0.93%
• Carbon dioxide (CO2): 0.04%
• Neon (Ne): 0.0018%
• Helium (He): 0.0005%
• Methane (CH4): 0.00017%
• Krypton (Kr): 0.0001%
• Hydrogen (H2): 0.00005%
• Nitrous oxide (N2O): 0.00003%
• Ozone (O3): 0.000004%

Water vapor and dust are also part of Earths atmosphere. It is important to note that the composition of the atmosphere can vary depending on location, altitude, and other factors.